The present invention is directed to a wrist support useful in combating the effects known as Carpal Tunnel Syndrome, and the method of making the same.
Carpal tunnel syndrome is a well known, commonly occurring hand condition, sometimes referred to as median compression neuropathy within the carpal canal. The most common symptoms of this condition include intermittent pain and numbness of the hand. Such pain or numbness results from compression of the median nerve which extends from the wrist centrally into the palm of the hand between the palm heel and the ball of the thumb. In carpal tunnel syndrome, a dense fibrous tissue called the transverse carpal ligament forms over the median nerve and compresses it, producing the symptoms of pain and numbness.
Treatment of carpal tunnel syndrome varies according to the severity of the condition. Severe conditions usually require hand surgery to sever the transverse carpal ligament. For less severe cases, the use of a splint which immobilizes the wrist is sometimes effective, often in combination with an anti-inflammatory medication. Such treatments are generally expensive, painful, and may reduce the patient""s ability to use the affected hand.
Carpal tunnel syndrome is a particular problem for workers in industries which require repeated manual operations with a held implement or tool. In many such industries it is a leading cause of workmen""s compensation claims.
Many different devices have been proposed for treating or preventing carpal tunnel syndrome. For example, protective gloves have been proposed as one means of preventing carpal tunnel syndrome due to wrist flexing. Berger U.S. Pat. No. 4,531,241 issued Jul. 30, 1985, describes a glove having a pad which covers the palm, wrist and a portion of the forearm. The glove restricts free action of the wrist. Fabry et al., U.S. Pat. No. 4,850,341 issued Jul. 25, 1989, describes a glove with a tapered pad designed for use by meat cutters or others using an implement with an action similar to using a knife. While this glove is useful for some applications, its pad configuration is not convenient for other types of actions in which the palm bends, particularly across the central fold of the hand. Fabry U.S. Pat. No. 5,214,799 issued Jun. 1, 1993, describes a glove for preventing carpal tunnel syndrome which has palm-covering padding to protect the wearer""s hand. The padding is made of a resilient flexible material such as foam rubber intended to provide protection from vibrations and shocks. The padding has a fold line extending diagonally across the palm to facilitate gripping the handle of an implement. All of these glove type braces and supports have the effect of unduly restricting the motion of the wearer""s hand.
Modern day keyboarding is a commonplace and widespread activity which is associated with Carpal Tunnel Syndrome, which is also referred to as Repetitive Motion Trauma. In response to this problem keyboard wrist rests and wrist supports have become ubiquitous. Keyboard wrist rests are manufactured in various widths for use with calculators, computer keyboards, typewriters and the like. These keyboard wrist rests are intended to keep the hands and wrists at a 15 degree angle, which is referred to as the neutral position.
Another type of wrist supports which are used may be classified as sewn orthopedic wrist supports or braces. These devices more or less encase the wrist and at least a portion of the hand. They are manufactured in various colors and provide three levels of support, light, medium and heavy. Those which are intended to provide light or medium support include elastic or neoprene material with a thumb-hole. The material wraps around the hand and wrist and is fastened with a hook and loop closure. Products for providing heavy support more closely resemble a brace, using plastic or metal strips called xe2x80x9cstaysxe2x80x9d as the means to obtain the rigidity necessary to stabilize and position the hand and wrist joint. It is uncomfortable to wear most such devices for keyboarding.
Still other devices which have been proposed for treating carpal tunnel syndrome include pull on supports or braces, plastic or metal splints secured by straps, bracelet like appliances, laced immobilizing braces, and wrist braces.
Peters U.S. Pat. No. 5,160,314 issued Nov. 3, 1992, describes a unitary body support adapted to be pulled onto and positioned about the hand and wrist area and adapted to anatomically conform to the wrist and basal hand of the wearer. The brace comprises a sleeve constructed of a resilient elasticized fabric including an outer layer having a brush ed looped texture. The sleeve is provided with a thumb opening and means for receiving a removable palmar stabilizing stay. The sleeve includes an integral compression strap which is sufficiently long to extend around the wrist at least once, and which is provided at its free end with hook attachment means for releasable engagement with the outer fabric loops.
Lemmen U.S. Pat. No. 5,417,645 issued May 23, 1995, describes an elongated flexible plastic or metal splint which extends from the center of the palm upwards along the wrist. It is secured in position by wrist and palmar strapping.
Eck U.S. Pat. No. 5,746,707 issued May 5, 1998 describes a wrist and two digit restraining device comprising a rigid metal or plastic splint element which receives the wrist, extends to support the heel and palm of the hand, and terminates at the base of the second, third and fourth fingers. Attachment straps are provided for the wrist support, thumb support and finger support. The device imposes a degree of restraint which would preclude keyboarding and many other activities.
Sucher U.S. Pat. No. 5,468,220 issued Nov. 21, 1995 describes a bracelet-like appliance which comprises a C-shaped member having a central portion located over the dorsal side of the wrist and two arms encircling the wrist. Each arm has a pad for engaging the palm near the attachment edges of the carpal ligament at the medial border and the lateral border of the carpal bones. The bracelet also includes a pad attached to the central portion for engaging the dorsal part of the wrist. The member is shaped to cause the pad attached to the central portion to press against the dorsal side of the wrist while the ends of each arm press in the opposite direction on the edges of the palm. The C-shaped member is a single piece of resilient, malleable material, such as aluminum, or is divided into sections interconnected by spring loaded hinges.
Harris et al. U.S. Pat. No. 5,769,804 issued Jun. 23, 1998 describes a laced wrist support comprising a preformed shell shaped to fit the patient""s wrist with a thumb hole through the shell for receiving the wearer""s thumb. An elastic tongue extends across the shell before being fully latched using a multi-strand lace extending over the elastic tongue. The multistrand lace is itself latched in place using a pair of self adhering hook and loop, fasteners.
Davini U.S. Pat. No. 5,385,537 issued Jan. 31, 1995 describes a wrist brace formed of semi-rigid material having a V-shaped cross section which cradles the wrist of the wearer. The semi-rigid brace is held in place by an attached flexible strap.
The invention relates to user wearable wrist supports and uses low temperature moldable, formable plastic, normally closed-cell foam, to replace the elastic material found in traditional wrist supports. This foam material is fabricated into the finished product using the improved method of the invention. The wrist support comprises a curvate clasp having a generally C shaped cross section, with the clasp encircling the wrist of the wearer. The clasp is secured by a strap, which may be formed during the wrist support fabrication.
In fabricating the wrist support, the material for forming the wrist support clasp is first prepared by forming a laminated composite material. The laminated composite material preferably comprises a flat sheet of a compressible heat formable closed cell foam, which is sandwiched between surface sheets of fabric. The fabrics are adhesively or otherwise attached to the sheet foam. The foam may be formed of any of a number of suitable synthetic materials, such as polypropylene, urethane, polyurethane, olefin, polyolefin, and similar materials. One example of such a material is a polyolefin film marketed under the trademark VOLARA.
The composite fabric-foam-fabric laminate is next clipper cut, die cut, or otherwise cut to the desired clasp body shape to create an uncompressed clasp body blank. The body blank is then subjected to selective compression and heat molding and forming into the desired C shape. It is in the nature of the closed cell foam of which the clasp is formed that it will retain its formed shape and density after the heat and pressure are removed. The compression is selectively applied, to provide in the C shaped body portion a sufficiently high density to furnish the desired flexible rigidity to hold the C shape. At the same time, according to one embodiment, the compression step provides more compression to create a securing tab or strap and an recess to receive the tab along with hook and loop securing material. The mold and compression are also such as to create an channel which receives a palmar stay.
In one embodiment of the method of the invention the stay is placed in position on the surface fabric on the uncompressed foam body blank. The positioned stay is then covered with a piece of cloth or fabric, and this fabric is sewn to the surface fabric to enclose the stay and hold it in position. The compression, heat treatment and molding then create the stay channel and fix the stay to the now formed clasp. The combination of the stay and the palmar support piece which covers it disposes the wrist and hand in the desired neutral or 15 degree position. In contrast to traditional wrist supports, the back of the hand is not covered by the support or restrained or immobilized.
In an alternative embodiment, the stay channel is defined by a pair of spaced parallel supports, which together form a channel between them. The stay is then positioned and secured at the bottom of the support flanked channel. The supports on either side of the stay perform the dual function of supporting the hand for keyboarding, while defining the channel which receives the palmar stay, which also provides support. The invention may further utilize an optional palmar strap to secure the palm and back of the hand to the palmar support piece, without imposing objectionable restraint on the hand motion necessary for comfortable keyboarding. The device of the invention is capable of performing the simultaneous functions of supporting the hand in the neutral position in the manner of a conventional stationary wrist rest for keyboarding, while at the same time providing carpal tunnel support for other activities in the manner of a carpal tunnel brace, all without imposing undue restraint on free hand motion.
According to a still further preferred embodiment of the invention the wrist support is formed from layered sheets of foam material which are of different hardness. The outer foam layer is of a higher density and is harder and more rigid than the softer and more flexible inner foam layer, which is in contact with the skin of the wearer. The outer layer is preferably formed of a material such as the previously mentioned polyolefin Volara, and is molded into a self supporting wrist encompassing bracelet or support having a generally C shaped cross section. The palmar stay is sandwiched between the outer and inner layers, which are attached to one another, such as by stitched edging. Additional stitching may be used around the periphery of the stay to secure it in position. This provides for a completely embedded palmar stay which is invisible to and is never brought into contact with the wearer. At the same time, the harder outer layer provides the desired self supporting rigidity to the curvate shape of the support.
A principle object of the present invention is to provide a wrist support directed to ensuring a neutral hand position of 15 degrees at all times when worn, as opposed to the stationary keyboard wrist rest, which works only when being used.
A further object of the present invention is to permit full finger dexterity because the back of the hand is not covered to the extent encountered with traditional wrist supports.
It is a further object of the invention to provide to the wearer of the wrist support a convenient means for customizing it to suit his or her preference. To this end a malleable, bendable, metal stay is incorporated in the product, and permits the user to increase or decrease the angle of support, unlike fixed keyboard wrist rests.
It is yet another object of the invention to eliminate the need for using both a stationary keyboard wrist rest and a worn wrist support, by uniquely incorporating the benefit of both products into one. This also eliminates the need for multiple keyboard wrist rests typically used by an individual. As a result of these combinations and eliminations, a significantly more functional and cost effective product is provided.
It is a further object of the invention to provide a method of fabricating a wrist support by cutting wrist support body blanks from a sheet of thermosetting foam laminated with fabric, selectively compressing at least one of the cut body blanks to form a compressed wrist support body having a tab integrally protruding from a first end portion, and having adjacent a second end of the body opposite to the first end an indentation to receive the tab, bending the body into an arcuate shape, and subjecting the bent body to heat so that it retains an arcuate shape.
It is yet another object of the invention to provide a wrist support which supports the hand of the wearer in a neutral position but permits unencumbered use of the hand.
It is a further object of the invention to provide a wrist support of the foregoing type having a stay and palmar pad which extend toward the palm substantially no farther than the heel of the hand.
It is another object of the invention to provide a self supporting C-shaped wrist support having a relatively hard surfaced outer layer, imparting the self support, and a relatively soft inner layer of a considerable thickness in contact with the wearer, the outer and inner layers having embedded therebetween a hidden stay controlling the position of the hand of the wearer.
It is yet another object of the invention to provide improved methodology for producing the wrist supports of the invention.